The Mole
... for anyone inspired to dig deeper into chemistry
Chocolate’s champion
chompability
Tom Husband melts into the sumptuous chemistry of chocolate’s
silky smooth texture
Issue 05 | September 2013
In this issue
Vitamin C
How a molecule
improved the
health of diseaseridden sailors
A global experiment
Join in with Avogadro's lab
Alien atmospheres
Cutting-edge chemistry
Piezoelectric
crystals
Secrets of the trade
L et's make this
work!
Life as a chemical engineer
Mole day
How will you celebrate?
© shutterstock
Editor
Karen J Ogilvie
Assistant editor
David Sait
Imagine yourself holding a bar of chocolate. As you tear
off the wrapper, you are greeted by the glossy sheen of
the chocolate. You break off a square with a satisfying
snap and place it on your tongue. The flavour intensifies
as the chocolate starts to melt in the warmth of your
mouth. Delicious compounds are unlocked while the
creamy mass glides across your taste buds. The flavour
of chocolate is sensational but the consistency – how it
feels to eat – is just as important. Not only did the cocoa
bean give us those wonderful flavours, it also gave
us another substance responsible for that trademark
consistency – cocoa butter.
Cocoa powder and cocoa butter are the two main
extracts from cocoa beans. Cocoa powder provides
the flavour, while the fat in cocoa butter provides the
texture. To make chocolate, the two substances are
mixed in different proportions and combined with other
ingredients, the amounts of which depend on the type
of chocolate being made. Dark chocolate contains
mainly cocoa powder, cocoa butter and sugar. Adding
milk to this combination creates milk chocolate. Finally,
white chocolate contains cocoa butter, milk and sugar
but no cocoa powder. Most chocolates also contain a
substance called lecithin, which is an emulsifier.
ChemNet content
Francesca Burgoyne
Production
Scott Ollington and Emma Shiells
Publisher
Bibiana Campos-Seijo
The Mole is published six times
a year by the Royal Society of
Chemistry, Thomas Graham
House, Cambridge,
CB4 0WF.
01223 420066
email: [email protected]
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© The Royal Society of Chemistry,
2013. ISSN: 2049-2634
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Registered charity number 207890
come in all kinds of shapes, sizes and colours. Some are
transparent, like quartz; others are opaque or shiny like
iron pyrite (‘fool’s gold’).
Fats are formed
from three fatty
acid molecules
attached to
a glycerol
molecule
Try it
yourself
Explore the structure and
melting point of chocolate
with this experiment,
which includes the
all-important taste test!
http://bit.ly/13171U2
But the thing that makes something a crystal is the way
the atoms, ions or molecules are arranged. In a crystal,
the structural pattern is fixed and repeats over and over
again, in all three dimensions. The smallest box you can
fit this fixed, repeating pattern into is called the unit cell.
Some unit cells are cubic, others are cuboids or rhombic
prisms, and the overall shape of the crystal reflects the
shape and symmetry of the unit cell. A crystal is a huge
stack of unit cells, all the same way up, side by side and
on top of each other, repeating over and over again,
right from one end of the crystal to the other.
The tantalising texture of chocolate is no accident.
Even after the ingredients have been combined in the
right amounts, the mixture still has to be tempered.
This is the process of manipulating a material’s
properties by changing its temperature. If the chocolate
is not tempered, it will not have the same glossy
appearance, satisfying snap and melt-in-the-mouth,
creamy consistency. For example, have you ever eaten
a chocolate bar that has melted in your pocket and
then resolidified before you opened the wrapper? It
looks dull or patchy, and feels grainy or greasy on your
tongue. The only way to restore the desirable properties
is to temper the chocolate again, to crystallise the cocoa
butter molecules in a particular way.
The crystal maze
Chocolate must be heated to
just the right temperature to
achieve the desired texture
and appearance
What pops into your head when you think of a crystal?
Chances are, you are thinking of the cubic crystals of
table sugar or table salt, or blue, parallelogram-shaped
crystals of hydrated copper sulfate. In fact, crystals
But how does this process of crystallisation relate to
the melt-in-the-mouth consistency of chocolate? The
first thing to note is the difference between a crystal
and a material that contains crystals. Chocolate can
form in various different shapes, Easter eggs being a
common example, and many of them do not look like
the crystals we just described. This is because a piece of
chocolate is not a single crystal. It is a mixture of several
substances, some of which form crystals. Each piece of
chocolate contains millions of microscopic crystals of
cocoa butter that are too small to see, mixed in with the
other ingredients that are not crystalline.
Fine forms of fat
To understand how cocoa butter crystallises, it is
important to know what kind of substance it is. Cocoa
butter is a fat, which means it is formed from three fatty
acid molecules attached to a glycerol molecule.
The fat molecules resemble the head of a fork with three
prongs. If we rotate one of the fatty acid chains so that it
sticks out the other side of the glycerol backbone, they
take on a new shape rather like a chair. This is important
because we need our cocoa butter molecules in the
chair shape to get the best crystals.
Not only is their shape important, but also the way they
are laid out. Remember that a crystalline structure is one
in which a pattern of atoms or molecules – the unit cell
– is repeated over and over throughout the structure.
The snag with cocoa butter is that lots of different
arrangements are possible. Another problem is that
no one is very sure precisely what those arrangements
really look like at the molecular level! However,
researchers and chocolate-makers agree that there are
six types, which are given Roman numerals. Types I to IV
produce inferior chocolate, while types V and VI give the
creamy texture and other desirable qualities.
© Mark Spowart / Alamy
While the structure of the type V and VI crystals is not
completely understood, there is a working model.
Returning to the idea of the ‘chair shaped’ fat molecules,
we think the unit cell for the type V crystal is with pairs
of chairs back to back and head to toe. These pairs can
then stack together to form layers, and several layers
stack on top of each other to make a crystal. But the
2 | The Mole | September 2013
www.rsc.org/TheMole
fat molecules could line up in the ‘fork’ position, or the
chairs could be back to back but not head to toe. These
are examples of what the structure of the inferior type I
to type IV crystals might look like.
Temper, temper
Now that we have identified the type of crystal we
want, we need to consider how to grow it. For this, two
things are necessary. The molecules forming the crystal
must be free to move and they need a lot of time to
get themselves lined up. This is exactly what happens
when chocolate is tempered.
Tempering chocolate involves repeatedly heating and
cooling the chocolate to allow the right kind of crystals
to form. Melting the chocolate allows the cocoa butter
molecules to move, and cooling the mixture slowly
gives them the time they need to arrange themselves
in the repeating pattern.
Same feel, less fat
Our understanding of chocolate is still
incomplete. But the more we learn,
the more advantages food chemistry
gives us. Up to now, the main point
of research has been to improve the
efficiency of the chocolate-making
process. For example, adding
emulsifiers such as lecithin has
helped to reduce a phenomenon
called ‘blooming’. This is when cocoa
butter molecules get pushed out
www.rsc.org/TheMole
But a far more exciting development in the world of
chocolate chemistry has just been announced by
researchers at the University of Warwick, UK. Stefan Bon
and his team have found a way to remove up to half of
the fat content of chocolate without affecting the flavour
or texture. This incredible breakthrough was achieved by
adding fruit juice or tiny blobs of jelly to the chocolate
mixture. After the ingredients have been mixed, there
is a very specific preparation process that has to be
applied, just as normal chocolate has to be tempered.
But the end product tastes just as delicious.
These breakthroughs show how rewarding a career in
chocolate chemistry could be. The huge profits of the food
industry will drive research for a long time to come. But
as the obesity epidemic continues, there is more than
money at stake. If you were the scientist to develop a
delicious chocolate with no fat and no sugar, history would
remember you as a saint – and a wealthy one at that.
© Richard Levine / Alamy
To solve this problem, the chocolate is heated up
again, this time to just 32oC. This melts all of the type
I to type IV crystals, while leaving the type V and VI
crystals intact, because they have a higher melting
point. Now, the only seeds present are the desirable
type V and VI crystals. As the remaining cocoa butter
molecules arrange themselves
around these seeds, they grow
into larger and larger type V and
VI crystals until the chocolate is
completely solidified.
of the middle of the chocolate and crystallise on the
surface, producing unsightly white patches.
Tempering helps the fat
molecules to achieve the
correct crystalline structure
Did you
know?
© rex / c. warner br / everett
In fact, the process is slightly more complicated than
that. First of all, the chocolate is heated to 50oC so
that it completely melts. Next, the mixture is cooled.
As it starts to solidify, the cocoa butter begins to
crystallise. But crystals of all six different types form.
At this stage, the crystals are very small and are called
seeds. In crystallography, a seed is a small crystal
and the starting point for a larger crystal to grow. The
problem after this first stage of tempering chocolate
is that the mixture contains seeds for all the different
types of cocoa butter crystals. This means that the
other cocoa butter molecules have a choice of seeds
to crystallise with, and whichever type of crystal a
seed is, it will stay that type. In other words, if a crystal
forms around a type II seed, then it will grow into a
type II crystal, and that is not the kind of crystal that
makes for good chocolate.
The chocolate river and
waterfall in the 2005 film
Charlie and the Chocolate
Factory weren’t computer
generated. Find out how
the film company
produced 1.25 million
litres of liquid ‘chocolate’
with this article from
Chemistry World:
http://rsc.li/15ElhAH
Food chemistry has helped
to prevent blooms of cocoa
butter molecules forming on
the surface of chocolate
September 2013 | The Mole | 3
Magnificent molecules
Vitamin C
Simon Cotton looks at the molecule that improved the
health of disease-ridden sailors
A cure
for colds?
Do you enjoy everything about Christmas except for the
brussels sprouts? Of course you might have heard people
saying that these vegetables are high in vitamin C. You
might be sick of people saying that’s why you should eat
them. But be aware that the ‘eat no fruit or veg for a year’
experiment has already been done, and it wasn’t pretty.
© shutterstock
Dietary deficiencies
Linus Pauling, winner of
Nobel prizes for both
chemistry and peace, was
convinced that taking large
doses of vitamin C would
stop people getting the
common cold, however
this is still to be proven.
It was in the early 15th century that the experiment first
began, although participation was not exactly voluntary.
Explorers and traders began to undertake huge voyages
to every corner of the globe, and sailors now spent longer
and longer periods at sea. Their diets were confined to
things that lasted for months, not days – meaning very
little fruit or vegetables, a lot of salted meat and biscuits,
and a serious lack of vitamins.
Vitamin deficiency can cause all sorts of health
trouble, but the sailors’ biggest problem was scurvy. Its
gruesome symptoms began with general lethargy, before
developing into spotted skin, rotten gums, bleeding from
open wounds and eventually death.
All was cloaked in mystery until 1747, when James
Lind proved that scurvy could be prevented by adding
citrus fruit to the diet. The British authorities were slow
to act on this, and it was only in the 1790s that daily
rations of lemon juice were introduced for all sailors. The
improvement in health was immediate, and this stood
the Royal Navy in good stead for the fierce battles of the
Napoleonic Wars. This was
the reason why British
sailors (and eventually
Brits in general) acquired
the nickname ‘Limeys’.
Ignorance
© shutterstock
Over a century would
pass before the effects of
vitamin C were understood
at the molecular level.
In the late 1920s, a
Hungarian named Albert
Szent-Györgyi was
studying antioxidants,
4 | The Mole | September 2013
and was convinced that a compound he isolated from
cattle was the scourge of scurvy, so to speak. He knew its
chemical formula, C6H8O6, but wasn't sure of its structure.
When he first submitted research on this new chemical
for publishing, he called it ‘ignose’, a candid admission of
ignorance that is certainly to be admired. Predictably, the
editor wasn’t happy with this, and asked him for another
name, so Szent-Györgyi suggested going a step further with
‘godnose’! In the end, however, he grudgingly accepted the
editor's more mundane suggestion of hexuronic acid.
Szent-Györgyi's research team found they could obtain
hexuronic acid from paprika, a cornerstone of Hungarian
cooking, and sent samples to Norman Haworth, a professor
of chemistry at the University of Birmingham. Haworth
was an expert on the chemistry of carbohydrates, and had
succeeded in deducing the structures of many of them.
Nobel prizes
Through some elegant chemistry, Haworth and his research
group soon worked out the structure of the molecule. A
pioneering x-ray diffraction study by Gordon Cox (also at
Birmingham) confirmed Haworth's structure.
Glen King at the University of Pittsburgh carried out tests on
guinea pigs with hexuronic acid in 1932 and showed it was
indeed the molecule that prevented scurvy. Szent-Györgyi
and Haworth were both to share Nobel prizes in 1937,
Haworth the prize for chemistry and Szent-Györgyi the prize
for physiology or medicine.
We now know that a shortage of vitamin C affects the
synthesis of collagen, the main constituent of connective
tissue. It is involved in the production of neurotransmitters
like dopamine and adrenaline, and also mops up free
radicals, protecting cells against damage.
The Latin noun for scurvy is scorbutus, leading to the
adjective scorbutic. In honour of its anti-scorbutic
properties, Szent-Györgyi and Haworth renamed hexuronic
acid as ascorbic acid, the name by which we know
vitamin C today.
Whatever you call it, this humble molecule plays a huge
role in the body, so the next time you contemplate going
on a year-long biscuit binge, remember the vitamin C!
www.rsc.org/TheMole
Chemistry Week
Avogadro’s lab
The Global Experiment
Chemistry Week this year runs from the 16–23
November and promises to be bursting full of activities
and events around the theme of health. One way you
can join in is to take part in the Global Experiment – the
Royal Society of Chemistry is asking people all over the
world to measure the amount of vitamin C in a range of
fruit and vegetables and compare their results online.
You could also make a video of your experiment and
upload that too.
You can do this on your own or find out if your teacher
will organise this with your class.
There are five steps:
1Download all the documents you need from the website
2 Calibrate your iodine solution
3 Prepare your samples
4 Carry out your tests
5 Upload and share your results online
Download the documents
The Global Experiment is based on our investigation of
vitamin C in orange juice in the last issue of The Mole,
but on a much bigger scale.
C
heck out the July issue of Avogadro’s lab
http://rsc.li/16e54Gi (this will remind you about
the chemistry behind the experiment).
G
o the Global Experiment website and download the
instructions: http://rsc.li/global-experiment
Calibrate your iodine solution
So your results can be easily compared with others,
you need to know how much of your iodine solution is
needed to oxidise a known amount of vitamin C. This
is called calibration and can be done using a soluble
vitamin C tablet, where the mass of vitamin C is shown
on the packaging.
Follow the calibration instructions to find out how many
milligrams of vitamin C react with one drop of iodine
solution. You are now ready to measure the vitamin C
content of a range of fruit and vegetables.
We suggest choosing from this list, as we will collect these
results online, but feel free to try some of your own.
www.rsc.org/TheMole
Fruits
Broccoli
Apple
Cabbage
Kiwi
Cauliflower
Orange
Potato
Pink grapefruit
Red pepper
Red tomato
Test your samples
Follow the method given in the instructions to test your
samples to find out how much vitamin C each one contains.
You could also try testing cooked samples and comparing
these vitamin C levels with the raw ones. You could also
try comparing fresh samples with older ones to find out if
the vitamin C content of a juice is affected by oxygen in the
atmosphere when it is left to stand, for example overnight.
Upload and compare your results
Now you can upload your results to the Global Experiment
website. Click the 'submit your experiment data' button
and follow the instructions on-screen to upload your data.
When you have uploaded your results you can compare
them with the data from all the other participants.
Watch the video
hwor th
See Stephen As
tly how to
ac
ex
ng
explaini
sts on
carr y out the te
:
riment website
pe
the Global Ex
7lXVAx
http://rsc.li/1
You can organise this data to find out all sorts of
information, such as what contains the most vitamin
C, does it make a difference if the samples are freshly
made or old, where in the world do fruit and veg with the
highest vitamin C content come from?
You can also export the data to a spreadsheet and find out
lots more information.
Did you
know?
Other things to try
If you have time, why stop at just testing raw and
cooked samples? You could try to find out if vitamin C is
extracted into cooking
water. Have fun
experimenting!
© shutterstock
Prepare your samples
Vegetables
© the hitman
Stephen Ashworth invites you to join in with
the Royal Society of Chemistry’s Global Experiment
Chemistry Week this year
takes place from 16-23
November. Events and
activities will be taking
place all around the
country. Details on what’s
going on and how you
can get involved will be
posted on
http://rsc.li/1du3vYJ
Much of the processed
food we buy has been
enriched with vitamins.
How does fresh orange
juice compare with a
processed juice drink?
Does the preparation for
canning or bottling reduce
the vitamin C content of
produce?
September 2013 | The Mole | 5
Cutting-edge chemistry
The chemistry of alien atmospheres
Have you ever wondered what a distant planet is made
of? Contented yourself with Wallace & Gromit’s cheese
hypothesis? Daniel Johnson wants you to think again
velocity of a body (the same effect that makes the siren
of a passing ambulance rise and fall in pitch).
The spectrometer has been in service since 2006;
astronomers have been using the Doppler shift to find
exoplanets for years. So what’s new?
© nasa
Well, previously astronomers measured the Doppler
shift in a star’s spectrum caused by the planet’s
gravitational field. The much heavier star barely moves,
spinning in a small circle at only a few kilometres per
hour. But Birkby and her team flipped this around, using
the Doppler shift caused by the planet’s motion around
the star (around 400,000 km h-1).
Black holes
and revelations
Britain’s first astronaut,
Helen Sharman, wrote
about the science of alien
planets and black holes
when the first planet from
another galaxy was
discovered in the Milky
Way: http://bit.ly/16xbYVj
6 | The Mole | September 2013
Astronomers using the European Southern
Observatory’s Very Large Telescope (VLT) have
developed a new method that could allow us to analyse
the make-up of exoplanets (planets outside of our solar
system) in greater detail than ever before. According to
results presented this summer, the new technique will
allow astronomers to ‘search for water on hundreds of
worlds without space-based telescopes’.
Hunting for water meant looking at longer wavelengths
where the Earth’s atmosphere starts to obstruct what
they are looking for. High in Chile’s Atacama Desert, the
VLT is ideally placed to minimise atmospheric effects,
but still the spectrum received a combination of signals:
from the exoplanet, the star itself and some distortion
owing to our atmosphere. However, the Doppler effect
shifted the exoplanet’s contribution while the rest
of the spectrum stayed the same. This is where the
spectrometer comes in. Its extremely high resolution
can distinguish individual water lines in the spectrum,
allowing the overall pattern to be identified.
A needle in a spectral haystack
An analogy for the process is this: imagine you’re
looking for a needle in a haystack. Unfortunately, the
needle is moving. You must discount the hay (the
spectrum of the star and atmospheric distortion) and
find the moving needle (the water signal). Your one
advantage? You know what the needle looks like.
The implications? It will be easier to look for planets that
may harbour those green aliens, for a start. Furthermore,
having improved the technique for water, the team, led
‘Of course we were delighted when we saw the signal jump
by Jayne Birkby of Leiden University, Netherlands, may
out at us,’ said Birkby, conveying her excitement that this
now move on to other atmospheric molecules such as
technique could be used ‘to look for Earth-twin planets’.
O2, CO2 and CH4.
The researchers can now move on to looking for more
Old principles, new method
atmospheric molecules, building up a picture of the
The method itself is a lesson in how old principles can
atmospheres and histories of thousands of exoplanets.
be combined to make huge advances. The technique
It raises the tantalising prospect of one day finding a
uses a high-resolution infrared spectrometer mounted
planet with a similar atmosphere to our own, where life
on the VLT. Just as important is the relationship between may have existed or even exists today. Then things really
the Doppler shift of electromagnetic radiation and the
get exciting.
www.rsc.org/TheMole
Electronic
tattoos
Flexible electronics
Emma Stoye investigates a super-stretchy conductor
© Joseph Xu/ University of Michigan
US researchers have made the stretchiest electrical
conductor yet using gold nanoparticles embedded in
an elastic polymer. The new material can stretch to over
five times its size while still conducting well enough to
power small devices.
Find out how temporary
tattoos containing flexible
electronics can be used to
monitor racing car drivers
with this article from
Chemistry World:
http://rsc.li/1ctlxsy
Finding materials that can conduct when stretched is
a huge challenge within flexible electronics. Existing
approaches, which involve coiling wires, liquid inks or
embedding conductive particles in stretchy materials,
have achieved limited success. The biggest hurdle,
says lead scientist Nicholas Kotov from the University of
Michigan, is combining two properties that counteract
each other. ‘If we increase the stretchability of a
material we automatically decrease the conductivity
because we are increasing the gap between the
conducting elements,’ he says. ‘On the other hand,
adding more conductive elements increases stiffness
and reduces stretchability.’
Nanoparticles
Kotov and his group have overcome this trade-off using
spherical gold nanoparticles dispersed through sheets
of polyurethane. When this approach has been tried
with other conductors, such as carbon nanotubes,
conductivity drops as the material is stretched. But
instead of spreading further apart when the material
is stretched, the gold nanoparticles form a branching
network of conductive chains so conductivity stays high.
‘We knew from our experience with nanoparticles in
solutions that a lot of particles have the ability to selforganise – it’s intrinsic to nanoscale matter,’ says Kotov.
‘Our approach worked really well – because of this self-
organisation we were able to get high conductivity and
amazing stretchability.’ He also says nanoparticles other
than gold could be used in the same way.
The new super-stretchy
material can still conduct
electricity when stretched
to five times its original size
Without stretching, the material has a high conductance
of 11,000 S cm-1. When stretched to over twice their
original length, conductance is 2400 S cm-1. It even
conducts when stretched to 5.8 times its length at
35 S cm-1, which is still enough to power some small
devices. This is a significant improvement on existing
stretchy carbon nanotube containing conductors, few of
which can even stretch more than twice their length, let
alone maintain conductivity.
Applications
There are several potential applications for such an elastic
conductor. Kotov says it could feature in flexible gadgets
or soft robots, and his group are currently trying to use it
to create soft, stretchable medical implants and sensors,
in particular for use in the brain.
© Joseph Xu/ University of Michigan
John Rogers, a nanofabrication expert at the University of
Illinois, Urbana-Champaign, US, agrees this is a promising
development. ‘These types of conducting materials could
provide new options in engineering design,’ he says.
‘The next steps will be to determine routes for integrating
these materials into functional systems and assessing
their performance compared to alternatives.’
www.rsc.org/TheMole
Scanning electron
microscopy image of the
flexible conductor when
it's stretched 110%
September 2013 | The Mole | 7
Trade secrets
Piezoelectric crystals
Did you
know?
© shutterstock
Gas lighters, mosquito bite relief and police sirens –
Jonathan Hare explores piezo chemistry in action!
When a piezoelectric crystal is bent or stressed the
distribution of charge inside the crystal changes.
This results in the creation of positive and negative
charges on opposite faces of the crystal, generating
a voltage. If we connect wires to the faces of the
crystal we can make use of this voltage. Examples of
piezoelectric materials include quartz, Rochelle salts
(potassium sodium tartrate), many plastics, table
sugar and even bone.
Bones show piezoelectric
properties. The effect is
thought to act as a
biological force sensor.
When you 'click' the button on a gas lighter, an
internal piezoelectric crystal is stressed, producing a
high voltage pulse (around 100–200 volts). The ends
of the two wires from the crystal are arranged so they
almost touch and the spark created by the voltage
pulse lights the gas.
Mosquito bites
There are all sorts of other day-to-day uses for
piezoelectricity. For example, while on holiday in
Greece this year I used a small piezo device to treat
mosquito bites and stings. The small electrical
shock created by the crystal is applied directly to the
skin around the bite. This inactivates the histamine
response that causes the itch, stopping the urge to
scratch and reducing the swelling.
Find out more
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The piezoelectric effect is reversible – if you apply
an alternating voltage to a crystal it will physically
oscillate. Piezoelectric transducers such as these can
produce very loud sounds and are used in smoke
detectors, alarms and police sirens.
Piezoelectric crystals were used in early electronic
record players. The crystal was attached to the needle
and as the record rotated, the groove vibrated the
crystal, creating a signal that could be amplified.
Try it yourself!
You can make Rochelle salt crystals yourself by reacting
warm aqueous solutions of potassium hydrogen
tartrate (cream of tartar) and sodium carbonate
(washing soda – both these chemicals are available
from a supermarket). Mix the solutions together and
over time crystals will drop out of the solution as it
cools. These can be used directly, or for growing larger
crystals from a saturated solution.
2KHC4H4O6(aq) + Na2CO3(aq) 
2KNaC4H4O6(aq) + CO2(g) + H2O(l)
You can test the micro-phonics of your crystal by wiring
it to the input of a set of powered computer speakers.
When you tap the crystal you can hear the 'tap' coming
out of the speakers.
Listening to dolphins
In the BBC TV series Rough Science, presenter Mike
Bullivant showed how to make some fantastic crystals
using this method. I fitted one of his smaller crystals to
a tin can (which acted as a diaphragm). With suitable
wiring and waterproofing I used it to make a very basic
hydrophone (an underwater microphone) to listen to
the fish and dolphins!
You can make a simple and cheap piezoelectric device
that creates enough energy to flash an LED when the
crystal is flicked. Find out how at http://bit.ly/14jnP8A
© shutterstock
Topaz crystals exhibit
piezoelectric properties
8 | The Mole | September 2013
www.rsc.org/TheMole
Matt Green
Pathway to
success
Graduate chemical engineer
at Atkins
2012–present
Graduate chemical engineer,
Atkins, Bristol, UK
2010–2011
Industrial placement,
Prysmian Cables and
Systems, Eastleigh, UK
Chemistry doesn’t stop until you reach
the final product. Daniel Johnson talks
to Matt Green about life as a chemical engineer
It was only by chance that Matt ventured down the
path to becoming a chemical engineer. A big fan of
chemistry at school, he had planned to continue his
studies at university, and was already attending open
days around the country. However, following a visit
to the University of Surrey, and with some time to
spare, serendipity intervened. ‘I had to fill a day and
we needed a second option, so I went to the chemical
engineering presentation.’
stored safely and using the minimum of space, and Matt
came up with improvements to the system. ‘I designed
a process, now used at a decommissioned power
station, which safely collects water from a drum of waste
material [decreasing its mass and volume].’ The water is
heated and driven out as vapour, then safely collected.
Radioactive metallic dust is scrubbed from the air by
filters for safe release to the atmosphere.’
That was all the inspiration Matt needed. ‘The work
seemed so hands on, people in hard hats on rigs and
things like that. The practical aspect of chemistry really
grabbed my imagination.’ He changed his application
to chemical engineering, and was accepted onto a
master’s degree at the University of Bath.
Matt’s current project is a response to problems
exposed by the Fukushima disaster in 2011. The
earthquake and tsunami waves knocked out power at
the Fukushima plant, disabling the nuclear reactors’
coolant pumps and sending them into meltdown. Matt
and his colleagues are working on contingency plans to
avert such a disaster in the UK. ‘After the earthquake,
EDF Energy [operator of all operating UK nuclear power
stations but one] decided that if anything were to
happen in the UK, we had to be able to react efficiently,
learning from what happened in Japan. The idea is that
a team can come in with self-sufficient cooling systems
that are compatible with the plant. We use big diesel V8
engines to power our equipment, creating units that can
safely deliver the [coolant] water we need at the right
pressure. It’s enterprising and always changing, so you
have to be really creative. No one has done a project of
this sort before.’
Let’s make this work
While at university, Matt landed a fourth year placement
at Prysmian Cables & Systems, a manufacturer of
telecommunications cables. He was struck by the
pragmatism needed to be a chemical engineer: ‘I
worked on the process of making large scale fibre-optic
cables. We started out with pellets of high-density
poly(ethene) (HDPE), before plastic-extruding them
onto optical fibres. There are 1000 different cable types,
and new types designed every week, which requires
a lot of imagination. Chemists’ input stops a long way
upstream, then the chemical engineers have to take the
materials and say: “Right, let’s make this work [as an
economically viable process]”.’
2005–2007
A-levels in chemistry, geology
and mathematics at Sedbergh
School, Cumbria, UK
Planning for the worst…
The world's first nuclear
reactor was constructed in
a disused rackets court.
Nuclear reactions are
controlled by ‘control rods’,
and in the first reactor the
safety measure for the
control rods failing to
operate was a man with an
axe ready to cut the ropes
that suspend them. This is
said to have led to the term
SCRAM (Safety Cut Rope
Axe Man), which is still
used today, although
SCRAM systems are now
fully automated!
…but hoping for the best
Since keeping the lights on with sustainable energy
sources is one of the biggest challenges we face over
the next few decades, it’s certainly going to be an
exciting time for young chemical engineers.
© shutterstock
Like many of his classmates, Matt had a graduate job
nailed down before finishing his course. The day before
his graduation, he began work as a chemical engineer
at Atkins, one of the world's leading design, engineering
and project management consultancies. He works in
the company’s energy business, specialising in nuclear
power generation.
2007–2012
Master’s degree in chemical
engineering, University of
Bath, UK
Radioactive packing
His first project was a small one by company standards,
but had a taste of the influential decisions a chemical
engineer has to make. Radioactive waste has to be
www.rsc.org/TheMole
September 2013 | The Mole | 9
RSC ChemNet Events
Dates for
your diary
Café scientifique: drugs
in sport
2 October 2013 19:00–21:00
Much Wenlock, Shropshire
Simon Cotton will discuss the
molecules at the heart of the
drugs in sport tale.
http://rsc.li/16uOYEb
Scifest – the chemistry
winners – celebration event
14 November 2013
10:30–14:30
Waterford Institute of
Technology, Ireland
This event showcases the
winning projects of the
Pharmachemical Ireland award.
Afterwards, Paul McCrory will
demonstrate entertaining ways
of understanding science.
http://rsc.li/16uPG4j
C
hemistry enhancement day
14 November 2013
09:00–12:45
University of Central Lancashire,
Preston
Enrich your understanding
of both of chemistry and
biochemistry with specialist
lectures, laboratory
demonstrations and tours around
world-leading laboratories.
http://rsc.li/16uQWoa
10 | The Mole | September 2013
Francesca Burgoyne takes a look at what the
winners of an RSC prize have been up to on
their laboratory placements
At The Big Bang in
March, two very talented
students were awarded
the Royal Society of
Chemistry Prize in the
prestigious National
Science and Engineering
Competition. Josh Sauer
and Emma Sharman
won £500 each for their
projects on molecular
level data processing
and improving diabetes
treatments respectively,
as well as a week’s
work experience in a
chemistry laboratory.
Find out in their own words what they got up to in the lab:
Josh Sauer
‘My A-level background was exclusively geared to
becoming a physical scientist of some description,
so I wanted to use this opportunity to open my mind
to other, less familiar areas of science. I chose a
biochemistry placement under the supervision of
Ulrike Eggert at Kings College London.
‘Dr Eggert’s research group is interested in the
chemical biology of the final step of cell division
– cytokinesis. One area they are investigating is a
© The Big Bang Fair 2013
Molecules of murder and
UCAS clinic
1 October 2013 17:45–20:00
University of Birmingham
Bring your UCAS questions to
the admissions tutors. What are
they looking for in a personal
statement? How do you impress
in an interview? The event is
followed by a lecture on the
molecules of murder by
John Emsley.
http://rsc.li/16uK3TZ
A winning experience
signalling pathway, the ‘Rho pathway’, which controls
cytokinesis. The group have discovered several
chemicals called ‘Rhodblocks’ that disrupt this
pathway so that they can see how particular proteins
take part in Rho signalling during cytokinesis.
‘During my placement I was taught about ‘RNA
interference’ (RNAi), a technique used by cell biologists
to silence specific genes. This in turn stops the
production of specific proteins. My project for the week
used a screening technique designed to observe either
The Big Bang
The Big Bang is the largest celebration of science,
technology, engineering and maths for young people
in the UK. The event brings science to life through
exciting interactive exhibits, demonstrations and
talks. Organisations from across the scientific spectrum give a flavour of the real scale of engineering
and science in the UK.
The event also hosts the finals of the National Science
and Engineering Competition. Come and find out
what other students have been up to with their
projects and investigations.
The 2014 fair will take place at The NEC, Birmingham,
from 13 to 16 March. It’s a great day out and there’s
no entry charge: www.thebigbangfair.co.uk
www.rsc.org/TheMole
Mole day
On 23 October each year,
from 6:02 am to 6:02 pm,
people across the world
celebrate Mole Day.
A mole is the number of
carbon atoms in 12.0 g of
carbon-12. This number is
huge – 6.02 x 1023 (602
followed by 21 zeros).
the suppression or enhancement of the RNAi effects
following treatment with the Rhoblock compounds.
6.02 x 1023 is known as
Avogadro’s number, named
after Lorenzo Romano
Amedeo Carlo Avogadro. He
first postulated that equal
volumes of any gas, under
the same conditions of
temperature and pressure,
contain equal numbers of
molecules.
Fly cells and microscopes
‘The technique involved staining samples of fly cells so
I could observe different parts of the cells fluorescing
under a microscope. We concluded from the data
that some of the Rhodblock derivatives were having
minimal effect on cells and needed to be at a much
higher concentration. To confirm our findings we also
conducted the same experiment on live human cancer
cells that had previously been treated with a protein
that makes them fluorescent.
‘I was introduced to spinning disk confocal microscopy,
which is able to take extremely high resolution pictures
in different focal planes. This is then used to build up a
detailed 3D ‘holograph’ of the sample. We viewed films
of the cells struggling to divide and again noted that the
Rhodblock derivative was having little observable effect.
them by customers or that have been produced by the
in-house laboratories.
Detecting water
Emma Sharman
‘During my week I gained a real insight into
analytical chemistry in an industrial setting. I learnt
how companies such as Onyx Scientific contribute
towards the pioneering work of some of the largest
pharmaceutical companies in the world.’
Emma’s placement was somewhere completely
different: she worked with a company that is involved
in manufacturing and research for large and small
pharmaceutical chemistry companies across the world.
‘Onyx Scientific is a company that provides
pharmaceutical chemistry services – customers
provide the company with a project brief, outlining
what work they would like to have completed. Some
customers ask Onyx to follow a method and produce
a particular substance: others want them to be
involved in the development process of making new
chemical compounds.
‘During my placement I was mainly based in the
analytical lab where I was shown how the analytical
machines work and what they are used for. The
analysts use a variety of different techniques to
examine chemical substances that have been sent to
www.rsc.org/TheMole
‘I had the opportunity to see a Karl Fischer titrator
in action – an instrument that can determine trace
amounts of water in a sample. I was also shown how
to service a liquid chromatography instrument. This is
used to separate components in a mixture in order to
identify and quantify each chemical.
Find out more at
www.moleday.org and
test your calculating
skills with this set of
mole calculations:
http://rsc.li/1bbwXxX
© the hitman
‘I learnt a huge amount about chemical biology over
the week and I was very humbled and honoured to
have assisted Dr Eggert’s team. I greatly enjoyed
learning about the complexities involved with
cytokinesis and the week has opened my eyes to many
fascinating and diverse research opportunities outside
physical science.’
It’s probably one of the
most important numbers
a chemist can know, as it
allows us to define how
much of a substance you
have. For example, if you
had a mole of sugar cubes
they would cover the
Earth’s surface to a depth
of 1170 m!
Have a go yourself!
The National Science and Engineering Competition
is open to all 11–18 year old students. It rewards
students who have achieved excellence in a science,
technology, engineering or maths project.
The competition is open for entries from January to
October each year. The chosen finalists are invited to
showcase their work to thousands of people at The
Big Bang Fair in March.
Entry is now open for the 2013–14 competition, so
why not give it a go? www.nsecuk.org
September 2013 | The Mole | 11
£50 of vouchers to be won
Chemical acrostic
Puzzles
Complete the grid (contributed by Simon Cotton) by answering the
nine clues to find the answer in the shaded box. This will spell out a
rare earth element.
Wordsearch
1
Find the 35 words/expressions associated with ruthenium compounds
hidden in this grid (contributed by Bert Neary). Words read in any
direction, but are always in a straight line. Some letters may be used
more than once. When you have found all the words, use the remaining
letters to make a seven-letter word.
T
2
3
4
5
6
T
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A
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M M O
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3 Important metal for our red blood cells
T
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4 Toxic in food but protective against x-rays and radioactivity
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6 Densest of all metals
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7 Milk and cheese supply this metal, which is vital for your body
S
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8 A metal used in making medical implants
S
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AIR
ANTI CANCER DRUGS
ANTI TUMOUR AGENT
AROMATIC RING
BIND
BLOOD
BOND
CELLS
CHEMICAL BOND
COLONY
COMPOUNDS
DNA
ELECTRONEGATIVITY
ELEMENTS
HYDROLYSED
HYDROPHOBIC
INERT
INHIBIT GROWTH
INORGANIC CHEMISTS
IN SITU
ION
IRON
LESS TOXIC
LIGAND EXCHANGE
MODE OF ACTION
ORGAN
OXIDATION STATE
RATE
REDUCED
SIDE EFFECTS
SPECIES
STATE
THEORY
TREATMENT
WATER
7
8
9
1 Essential element to make Pyrex glass
2 Metal added to some socks to kill odour-causing bacteria
5 Deadly poisonous metal, accumulated up food chains
9 A low density metal, used to make take-away meal containers
E
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The winner was Aylin Efe from London. The 10-letter word was SUBSTRATE.
T
by Monday 28 October.
A correct answer for each puzzle, chosen at
random, will win a £25 Amazon voucher.
O
N
July wordsearch solution and winner
Submit your answers online at
http://svy.mk/TM513ans
C
July acrostic solution and winner
The winner was Analia Cho from Chile
I
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